The TB bubble test is the visible reaction to the Mantoux tuberculin skin test, indicating the injection of a small amount of fluid under the skin to test for tuberculosis (TB) exposure.
Here's a more detailed explanation:
-
The Mantoux Test: This test, also known as the TB skin test, is the standard method of determining if a person has been infected with Mycobacterium tuberculosis, the bacteria that causes TB.
-
The Injection: A nurse or healthcare professional injects a small amount of fluid called tuberculin into the skin on the lower part of your arm (usually the left forearm).
-
The "Bubble" or Wheal: As the fluid is injected, a small, raised bump, also known as a wheal or "bubble," will immediately appear at the injection site. This signifies that the tuberculin has been correctly administered into the skin.
-
What it means: The presence of this initial bubble simply indicates the injection was performed properly. It's not a sign of a positive or negative result. The test result is determined 48 to 72 hours after the injection by measuring the induration (a raised, hardened area) around the injection site.
-
Reading the Test: A healthcare provider will examine the injection site after 48-72 hours to see if there's a reaction. If there is a raised, hard area, it means you've probably been exposed to TB at some point. The size of this area will determine whether the test is considered positive. A positive skin test only indicates TB infection, not necessarily active TB disease. Further tests, such as a chest X-ray and sputum samples, are needed to determine if the person has active TB disease.
